Phoenix
by The Lady Rogue
Summary: Suddenly Phoenix shifted from lax to alert and he rose from his seat. He paced toward the corridor and leaned against the wall with one hand, reminding her of a tiger stalking his prey. Natasha shivered and placed a hand on her gun. "Hello Nick," Phoenix purred. "I hear you've been playing with the big boy toys and you didn't think to invite me." *W.I.P.*
1. Chapter 1

There was a man sitting at the table on the upper deck of the Helicarrier that Natasha had never seen before. He was lounging in a chair, feet propped up before him, arms crossed, and a furious look upon his face. He was dressed in combat fatigues and she could count six obvious weapons on his person, and suspected there were many more. He had dark hair and eyes that were even greener than her own that inspected her as she walked in. Hill was hovering next to him, one hand on her head piece as she muttered quietly into the mike.

"Who're you?" Steve demanded from behind her. The man surveyed then dismissed him, glancing around the ship.

Banner was also seated at the table, as far away from the man as he could possibly get, his knuckles white from where they were clenched into fists. He was studiously not looking at the man and Natasha didn't blame him. There was something about him that screamed danger and Natasha trusted her instincts implicitly.

"This is Phoenix," Hill said when it became evident that the man wasn't going to answer Steve. Phoenix's lip curled, but he didn't refute her claim.

Suddenly Phoenix shifted from lax to alert and he rose from his seat. He paced toward the corridor and leaned against the wall with one hand on his hip, reminding her of a tiger stalking his prey. Natasha shivered and placed a hand on her gun.

"Hello Nick," Phoenix purred. "I hear you've been playing with the big boy toys and you didn't think to invite me."

Fury strode onto the command deck, brushing past Phoenix. Natasha couldn't help but notice that he too stayed as far away from the other man as he could without seeming intimidated.

"How the hell did you find out about this?" Fury growled.

Phoenix smirked. "Really, what you should be asking yourself is how the hell did you think that I wouldn't?"

Fury's face twisted with distaste, but he nodded. "Shall I bring you up to speed?" he asked.

Phoenix scoffed. "Don't bother. I think I'll go take a look at that sceptre now." Phoenix stalked away, and the sixth sense that kept her aware of his every movement faded to a low hum from an insistent buzzing.

Stark walked in moments later, looking paler than usual. "Who was that?"

Fury just shook his head.

"Did you call in Phoenix?" Phil asked, hot on Stark's heels. "Because he just walked past us in a hell of a mood."

Fury actually huffed. "No, but he damn well turned up anyway. You know what he's like."

Phil pursed his lips. "Unfortunately," he muttered.

Fury pinched the bridge of his nose. "Coulson, brief Romanov and get her to run damage control. The rest of you, let's focus on finding the Tesseract."

Phil inclined his head and she followed him out and into a separate conference room.

"This is security clearance 8," Phil announced, activating the highest level of security a room could have on the helicarrier. Shutters slammed closed over the windows and Natasha placed her electrical devices into the lead box supplied; the most complicated piece of tech left on in the room were the lights. She took a seat while Phil paced before her.

"Have you heard of the Multiverse Theory?"

"Infinite parallel universes," Natasha replied, intrigued. "Yeah."

"It's not a theory. Phoenix is an ancient immortal from another dimension."

Natasha raised a brow. "Ancient as in…"

Phil shrugged. "We don't know how old he is, but we've found evidence hinting to his existence on Earth dating back to at least the American Revolution. He's British, so he may have been in Europe even before that. He claims that he stayed in his own dimension until Earth became uninhabitable, after which he decided to 'move' to a universe where there was extra-terrestrial life other than humans." Phil sighed. "Our scientists say it could be up to a billion years until that could happen, as least in our universe. Take it as you please."

Natasha was sitting very still as she tried to get control of her emotions. A potentially billion-year-old immortal. No wonder her senses had been going haywire.

"Our expert psychologists think it's only a few thousand years, if that helps. Any longer and he'd be even more apathetic than he already is. Currently, he's chosen the path of least resistance; helping SHIELD, at least when he's inclined."

She took a deep breath. "What do you want me to do? Seduce him?"

"No!" Phil's eyes were wide. "Don't try to manipulate him, he loathes deception. Be blunt, be honest, don't hold back, just talk to him. The only people we've observed him interacting with in a non-apathetic manner are children and attractive, red headed woman, and even then..." He shrugged.

"And I fit the bill," Natasha murmured. "I'll go down to the lab then."

Phil dismantled the security around the room.

"Be careful," he called as she walked out.

* * *

Harry stared at the sceptre and got the distinct feeling that the sceptre was staring back at him. He ran one finger up the handle, brushing away its attempts to insinuate itself within his mind. He focused on the gem that was pulsing with energy. Did Fury realise what he had within his reach?

"So you're the sacrificial lamb?" Harry commented to Agent Natasha Romanov as she walked in. He could feel her amusement, albeit tinged with a hint of fear. So they'd given her the run down. Understandable, really.

"If you want to look at it that way," she responded. Harry turned, let his gaze drift over her. She was stunning, especially in the skin tight latex suit they had her wearing. She had the customary scarlet hair of the woman that Fury tried to throw at him.

"You're probably the reason those suits were created," he muttered and turned back to the sceptre. He cupped the gem between his hands, careful not to touch. There was a protective layer… but underneath was something he couldn't let anyone else in the universe get their hands on. Not if he wanted it to last longer than his old world. He tapped his fingers along the metal workbench the sceptre was sitting upon, then crooked one finger at Romanov.

"Come tell an old man what you feel when you stand near this," he said.

"Old?" Stark scoffed from somewhere behind him. He and Banner had followed Romanov in. "You're barely past twenty."

He felt, rather than heard, Romanov suppress a flinch. Harry smiled. "Well?"

She shook her head as if attempting to clear it and one hand drifted closer to the staff. "I feel… I feel as if I could do anything. So fed up with these sexists jobs, don't they know who I am? I could take you down, and Stark, and что гребаный монстр баннер, я убью вас всех![1]" she snarled. Harry chuckled and captured her wrist before she could pick the staff up. He yanked her back and shoved her into a wall.

"Соберись, маленький паук,[2]" he murmured. She blinked, then pressed the palms of her hands into her eyes.

"Что, ебать, это было?[3]"

Harry smiled, ignoring the banal reactions of the two other men, squawking like parakeets.

"A very dangerous weapon and the reason Barton's compromised."

Romanov nodded, eying the staff with distaste.

"Sorry about this," Harry said, more out of habit than anything else. He clasped one hand around the protective casing on the gem and squeezed. The blue energy exploded in a flash of light and alarms started blaring. Glass shattered and the lights flickered.

Pain. Such pain. Pain like walking into the supernova of a star, pain like exposing himself to the vacuum of space, pain like trying to atomise every particle in his body. Harry wrenched the gem from the sceptre and pressed it into his chest. Energy danced in the air, curling around his body. It sank into his very being and tried to remake him in its image. No. Harry growled. I am the Master of Death and I will have you. The stone flared, attempting one last time to rend him from existence but Harry exerted his will over the Mind Stone and pressed. He pressed and pressed and forced it into submission until it settled calmly in his veins.

When Harry came to he realised that he was kneeling on the floor.

"Fuck," he swore. He touched one hand to his potions pouch and a headache remedy appeared in his hand. He downed it quickly then staggered to his feet. The lab was ruined. Stark had encased himself in his suit, shielding Banner, who'd impressively not turned green. Harry lazily waved his hand and restored the room to its previous state.

Minds pressed on him from the entire world, from the entire solar system, from the entire universe and Harry was overwhelmed with their pain and joy and suffering and pleasure. He slammed down his Occlumency barriers, only allowing the minds within a fifty-meter perimeter entry before he lost his questionable sanity, then he turned incredulously to Stark.

How did he repair the room. Magic? No. Magic is just science we don't yet understand. Did JARVIS get any of the readings? He's glowing golden. It looks hot. He's hot. Romanov's hot. Banner's mind is hot. Can Banner control the change? Obviously. Where's Agent Agent when you need him? Sucking up to Capiscle probably. He's also hot. Phoenix is staring at me. Those eyes can't be natural. Can that shade of green be replicated? Pepper would look good in a dress that colour. She's hot. She's very hot. Stop! Focus on Phoenix. Why did he destroy the staff? What was that gem? Obviously a power source. What kind? Like the Tesseract? Did he absorb it? He's dangerous. Still hot though.

"You think way too fucking fast," Harry said.

"You can read minds?" Stark blurted out. Could he before? Did the gem give him that power? The glowing's fading. Fury's gonna be pissed. Can I work that to my advantage? Why did… Harry tuned Stark out, as amusing as he was to listen to, as three other approaching minds were of more interest. Rogers, Coulson, and Fury burst into the room. Harry grinned.

"I think it's time I had a little talk with Loki," Harry said and Apparated silently into Loki's cell.

Loki's back was to him, but he stiffened the moment Harry arrived.

"You're no mortal," Loki said. Harry chuckled. He leaned back against the glass and ran a hand through his hair.

"Quite the opposite," Harry agreed. He absently began drawing runes on the glass with one finger. "Tell me, did you know that you had the Mind Stone in your possession?"

Loki frowned. "The what?"

Harry laughed. He couldn't help it. He lowered his voice, pitching it so it was barely above a whisper. "Before creation itself, there were six singularities. Then the universe exploded into existence and the remnants of these systems were forged into concentrated ingots… The Infinity Stones."

Loki paced back and forth. "What of it?" But there was an anxious gleam to his eye. Harry tugged on the thread connecting Loki to the Mind Stone and Loki stiffened.

"What have you done?" Loki hissed. Harry smirked. He twitched his finger and Loki fell to his knees.

"I've claimed possession of the Mind Stone, of course. Thanos has been using it to control you, hasn't he?" Harry stroked a finger along Loki's cheekbone. He drew the finger up, then pressed it to Loki's forehead, curling the connection around it. When he snapped his finger away the connection came with it and Loki slumped to the floor with a groan.

Harry Apparated out of the cell and activated the runes he'd drawn on the glass. No one could get in without actually opening the cage and Loki couldn't get out. "Don't go anywhere," he said.

"Who are you?" Loki cried, even as his eyes faded from bright blue to forest green.

"I'm the Master of Death," Harry cheerfully replied. "And I think it's about time I stared behaving like it." He turned on one foot and Disapparated away.

* * *

 _Russian translation, thanks google translate._  
 _[1] and that fucking monster Banner, I'll kill you all._  
 _[2] Pull yourself together, little spider._  
 _[3] What the fuck was that?_


	2. Chapter 2

By the time they'd managed to get down to Loki's cell, Phoenix was gone, and Loki was crumpled up on the floor. Every camera in the vicinity had gone dark the moment Phoenix had disappeared from the lab, so they had no idea what had happened.

"Brother!" Thor cried, kneeling next to the glass and pressing his hands against it. Loki groaned.

"Thor." Loki pushed himself to his knees and placed his hands against Thor's on the glass.

"I've made a terrible mistake," Loki rasped. "I thought you would be lesser of two evils." He chuckled, then began to cackle madly. Natasha exchanged a worried glance with Phil.

"Barton's just got in contact," Fury hissed beside her. "Said his mind cleared and then moments later Phoenix made off with the cube."

Loki laughed harder, glancing over at them. "You're doomed!" he muttered. "All doomed."

"What have you done?" Thor growled.

"Me? Nothing? Just submitted to another's rule. But now I am free, my mind is my own, and the Master of Death walks the stars, in possession of three Infinity Stones."

"The Tesseract," Thor stated. "That's is one. The Stone of Souls, that is another."

"What's an infinity stone?" Natasha interrupted. "Who's the Master of Death?"

"And the third?" Thor continued. Loki beamed and his eyes were mad.

"Why, the Mind Stone powered my sceptre."

Thor turned to them, his eyes narrowed. "Who did you invite onto this ship?" he said quietly, but there was a threat in his words.

"An operative," Fury replied. "His name is Phoenix and he invited himself."

"He took the stone from the sceptre and absorbed it." Natasha said.

"Mortals!" Thor spat. The tips of his fingers began to crackle with electricity. "Always playing around with that which they do not understand. How did you happen upon the Master of Death?"

Fury looked defeated. "We offered him a job."

The hairs on the back of Natasha's neck prickled. She turned, taking in Loki's narrowed eyes. He was gazing into the shadows.

A gleaming pair of emerald eyes gazed back. Natasha shivered. She edged away from the posturing between Thor and Fury and walked toward Phoenix.

She meant to stop outside of his reach, but he surged forward and wrapped his arms around her. The world lurched and moments later they were standing atop Stark Tower.

"Hello . little spider," Phoenix said. She wrenched herself out of his grip.

There was a device sitting on the rooftop and Eric Selvig was sprawled upon the ground next to it. She crouched by him and checked his pulse.

"He's unconscious," Phoenix said. He waved his hand and two armchairs appeared. He seated himself in one. Natasha took the other. It would be rude not to.

They sat in silence for long seconds that stretched into minutes and eventually Phoenix chuckled.

"I like you," he said.

"What's your name?" Natasha asked. Phoenix quirked his lips into a smile.

"Which one?" She stared at him blankly and he smirked. "Call me Harry."

"Harry," Natasha tried. He didn't look much like a Harry, but then again, he didn't much look as if any human name could fully describe him, with eyes that glowed too bright, and his skin an ethereal gold.

Harry stretched, arching his back. "Mm?"

"I don't suppose you'll explain this mess to me?" she asked, not bothering to get her hopes up. Harry considered her, then he snorted.

"Damn it, but they're right." He winked at her. "I've always had a weakness for red heads. Go on. I'll answer three questions."

Natasha paused to consider her options and decided on a question that would hopefully help determine the rest.

"What's an infinity stone?"

"An incredibly powerful semi-sentient gem that allow manipulation of the universe at a subatomic level. There are six, of which I possess three: Mind, Space, and Soul. Reality, Power and Time are scattered, however I suspect that they are closer than one might think." For a moment Harry glanced toward the sea.

"Loki said that you're the Master of Death," Natasha said. Harry arched a brow in amusement.

She narrowed her eyes. "What is the Master of Death?"

"In my own reality I collected three items; The Resurrection Stone, The Cloak of Invisibility, and the Death Stick. It was said that those whom collected all three would master death. It is a curse. I shall never age, never die, always continue as all things fade."

At the look upon Harry's face Natasha could believe that he'd lived for billions of years. He seemed ancient, beyond mortality, beyond the petty squabbles of humanity.

Then Harry shook his head, as if to clear his mind. "Last question." His eyes gleamed.

Natasha tilted her head and decided to be blunt. "Are you a threat, in any way, to this world?"

Harry smiled. "A good question, one that is far too complex to answer completely. Do I want to preserve this world, and life upon it? Yes. Am I threat?" He smirked. "What do you think?"

He disappeared, his armchair with him, and Natasha leapt to her feet just as her own vanished into thin air.

Did she think he was a threat? Unequivocally. But Natasha knew all about picking the lesser of two evils. Perhaps she was being naïve when she thought that he had no interest in causing harm. He was dangerous, certainly, but she didn't think he'd flee his home world in order to destroy another.

That was what she had to hope for.

* * *

If Harry wasn't careful, he could easily be caught in Natasha's web. Caught and comfortable with it, satisfied with his place as a pawn of Fury or another short-sighted mortal.

The Infinity Stones throbbed within his soul and he calmed himself. It would not do for Harry Potter's infamous anger to rule him, not when he had the power to level planets and warp worlds.

With barely a thought he found himself in Nepal. It was a moment's work to enter the Kamar-Taj, and the gentle caress of the Mind Stone encouraged those that might apprehend him to look elsewhere.

He walked calmly to the Eye of Agamotto, or as it was more commonly known, the Time Stone.

The glowing gem pulsed the same emerald as his eyes. As Harry passed his hand over it, the other Infinity Stones surged within him.

Earth itself screams as a pulsing ball of indigo matter spews from the crater that was once Hong Kong, consuming everything it touches. Black tendrils creep forward, cleaving mountains in half, while dark energy engulfs the very world it lives on. All the powers in the universe are nothing against an empty maw that forever craves more. A black hole forms, the universe collapsing in on itself as the Dark Dimension devours everything that ever existed and ever will. Beware… Beware…

BEWARE.

Harry staggered backwards, wrenching his hand from the Time Stone.

"It can be like that, sometimes."

He spun, coming face to face with the being known as The Ancient One. Her hands were clasped behind her back, but he knew very well that wouldn't stop her from attacking him, should she wish.

"I will not take it," Harry said. "It is still needed here." He narrowed his eyes, refusing to be cowed by a woman he'd known as a child.

"Beware your arrogance, Harry," she said, her words a whisper on the air as he transported himself to London.

* * *

"All this, and you're telling me Loki's not the problem?" Stark snarled. Natasha rolled her eyes and Clint smirked at her.

"For someone that claims to be so intelligent, you don't like to listen, do you?" Steve said, crossing his arms.

"Enough," Fury growled. "Posturing isn't going to solve anything. We've already determined that Loki was operating under the same influence that Clint and Selvig were and we know that the Chitauri can't arrive without the Space Stone. Let's focus on the real threat."

"Phoenix?" Clint said. He tilted his head to one side. "I rather liked him."

"Right," Stark drawled.

"Did you ever meet him?" Natasha asked incredulously, while Steve and Stark resumed their bickering.

"Yeah, ran a few ops with him. Funny guy."

Natasha didn't bother to hide her frown. "He didn't feel a bit… off, to you?"

Clint shrugged. "Not really. He's bloody scary with a knife, but it wasn't like I ever thought he was any kind of threat."

"He felt dangerous to me, even from a distance," Banner said quietly.

Clint cleared his throat. "Who here got the heebie-jeebies from Phoenix?" he asked the room at large.

"Yup." Stark popped the 'p'. Steve nodded sharply.

Hill exchanged a glance with Fury. "He almost seemed to have an aura of danger about him," she said. "I'd dismissed it, prior to discovering magic."

"I found him unsettling," Natasha said.

"The Other Guy really didn't like him," Banner added.

"There was always something… different, about him," Phil said, ever the diplomat.

"Even now, I can still smell the stench of his magic," Thor said. "Death, and decay."

"You can smell his magic," Fury said incredulously.

Thor grimaced. "It is a translation error. You humans do not have the sense for it, thus do not have the necessary words to describe it."

"Great," Stark muttered. "Thanks for that, real useful."

Steve cleared his throat. "Let's start with what we know and work from there, okay?"

"I'll dig up what I can find online," Stark said.

"I can keep working on an algorithm to find the Tesseract?" Banner offered.

"I'll talk to Loki," Natasha said.

"I'll give him a call," Clint said. There was a beat of silence as everyone turned to stare at Clint, who shrugged. "What? He gave me his cell number."

Stark banged his forehead into the table. "I – am – surrounded – by – idiots," he said, each word intermittent with another bang.

"I read that you lose brain cells doing that," Clint said.

Stark glared at him. "Give me his number, Birdboy, and I can use it to triangulate his location."

Clint slid his phone over and Natasha slapped the back of his head. "идиот.[4]"

* * *

 _[4] idiot_


	3. Chapter 3

Harry felt a sense of nostalgia whenever he visited London. It took him back to days of living with Ginny, nights spent drinking too much with Ron, and being nagged by Hermione, before he'd realised he'd stopped aging. The pain of their deaths had ceased to hurt hundreds of years ago, but he would never forget his oldest and truest friends.

There were no Weasleys in this world, as there was no magic, but a Muggle Hermione Granger existed. She had two doctorates and was currently studying for the Bar. There was a café in London that she frequented and today was one such day. He bought himself a coffee and sat with a paper, trying not to stare.

"You may as well go chat to her."

Harry jumped, and looked guiltily away from Hermione to the man that had spoken to him.

"Hawkeye?" he said incredulously, then grinned. He swept the other man into a hug. His gaze flicked around the room, noting that a wide-eyed barista was quietly speaking to each of the customers, evacuating the café.

"You don't have to kick everyone else out," he said. "That's just rude. This is the greatest cup of coffee in Westminster."

Chagrin crossed Clint's face. "Not my call,"

Harry smirked. "No, I suspect not. There a perimeter around the building?"

Clint didn't answer. He didn't have to.

Harry shook his head. "What a waste of resources." He pulled the phone that they must have used to track him out of his pocket, then flicked his fingers at Clint. Several devices screeched, then died a sad electronic death. The CCTV camera exploded, and Harry made a mental note to send an anonymous donation to the shop.

"Fancy seeing where I grew up?" he offered, while Clint pulled his earpiece out with a disgruntled look upon his face.

"I'm not sure I have a choice."

Harry frowned. "You always have a choice. Say no, walk away from here without another word. I'd let you go, of course. Say yes, go on an adventure. Or counter my offer with something more exciting."

Clint rolled his eyes and punched him on the shoulder. "Dick. Go on then."

Harry grabbed his arm and they Disapparated.

* * *

"Fuck," Fury said, as all of their cameras shorted out.

Natasha pursed her lips. She wasn't sure how Fury hadn't seen that coming. Stark was muttering profanities about his precious electronics being fried, but there was a curious expression on Banner's face that was only matched by contemplative one on Steve's.

"For one second, let's forget that Phoenix has made off with the Tesseract, a device that could be argued isn't even ours to lay claim to," Steve said. Fury glared at him, but Steve barrelled on. "Nothing else he's done has actually been detrimental to SHIELD."

"He even helped us, helped Loki," Banner said.

"He seems to genuinely like Clint," Steve said. "That sort of interaction is hard to fake."

Fury crossed his arms. "What are you trying to say?"

Natasha exchanged a glance with Steve.

"Treating him like he's the enemy isn't going to help anyone's cause," she eventually said, intrigued to see where Steve was going with this.

Banner cleaned his glasses on his shirt. "I'm, a, well, I'm a class five threat, but you seemed satisfied to just monitor me, or so you say."

"Treat him the same," Stark pondered. "Definitely better than trying to hunt him around the globe."

"Not even Loki has the same teleportation capabilities," Thor said. He'd been quiet observing until then. "You have no means to contain him and I do not even know if Asgard has the technology." He huffed. "Not that we would even try."

* * *

"Dude, you're an immortal being from another universe and you grew up in this cookie cutter suburban hell?"

Harry glanced around Privet Drive. It was just as he remembered.

"Yeah. Mr and Mrs Dursley, of number 4 Privet Drive, were proud to say that they were perfectly normal, thank you very much," he said and grimaced.

"No shit," Clint said. Harry imagined he could see Petunia peering out, gazing at the two strange men standing outside her house.

"This is where I grew up, but it wasn't my home." He grabbed Clint's shoulder and Apparated them to Hogwarts.

It was a ruin, owned by the National Trust, a far sight from the thriving castle it had been the last time he'd seen it.

"This pile of stone?"

Harry laughed. He brushed his hand over Clint's eyes. Clint gasped when he opened them again.

"Wow," he said with feeling.

"Yeah," Harry agreed. He'd given him the view of Hogwarts that every first year saw on their approach to the castle. Breath-taking, heart-stopping, made of dreams and magic.

"It was a school, my school, of people like me." He ambled around the Black Lake, Clint a few steps behind him. "Mermaids and a giant squid lived the lake. Unicorns dwelled in the forest, and children raced about the halls of the castle." He added these to the illusion he'd created. "Hagrid's hut," he said, gesturing as the wooden cottage came to life. He paused, then recreated himself, Ron and Hermione leaning against one of the boulders that dotted the grounds, after the war, enjoying the sunshine and peace of eight year.

"It's wonderful," Clint said. Harry smiled, and let the illusion fall away, leaving behind moss covered relics of an age long gone.

"That it was," Harry agreed.

"So, I don't suppose I can persuade you to return the Tesseract?" Clint said.

"I'm afraid not."

Clint snorted. "You're a right bastard, Phoenix."

Harry shrugged. "I'll give you a lift back home to make it up to you. Or to the helicarrier?"

Clint smirked. "Think you can get me into Fury's office undetected?"

"Of course."

* * *

Three shots rang out from Fury's office just after he disappeared into it and Natasha sprinted back down the corridor.

"Woah, easy!" Clint cried. "Do I look like a brain washed sycophant?"

Fury was standing with his gun levelled at Clint, a fierce expression on his face. "How did you get in here?" he growled.

"My apologies," Harry said. Natasha spun, but didn't bother pulling her gun. He was standing behind the desk, examining the paperwork. "That was my doing."

He was smirking, the arrogant pillock. "I believe you wanted to talk to me?"

Clint snickered as he left the room, but Fury stopped Natasha from following. She leaned against the wall and said nothing. Harry shot her a look of amusement, but turned back to Fury.

"What are you doing here?" Fury asked.

Harry looked faux offended. "I'm giving in my two weeks notice."

"Two weeks… you're fired, is what you are. That's the second time you've kidnapped one my employees, not to mention stealing the Tesseract."

Harry shrugged. "The Tesseract was too dangerous to leave in mortal hands."

Fury's finger twitched, as if he wanted to empty his clip into Harry and find out just how 'immortal' he was. Harry seemed to be able to tell, as his smile widened. Natasha shivered.

"Anything else?" Fury growled.

Harry tilted his head. "No, I don't think so."

He disappeared with a loud crack.

"Displaced air," Stark said from the doorway. "That's what that sound is." He was eyeing the empty space with an intrigued look.

"Do I look like I care?" Fury said, turning to scowl at Stark.

Stark smirked. "So, I've compiled a history of Agent Phoenix, AKA, Harry Potter, AKA many other aliases."

Fury sighed. He strode round to take his seat and beckoned them both in.

"I've got JARVIS running facial rec, on, well, pretty much everything. Photos, paintings, murals, anything we can find. He first appears in the UK, the 1700s, as Henry, Duke of Cumberland. His marriage to a commoner actually instigated the 1772 Royal Marriages Act. Then he migrates to America, Australia, America and then back to Europe as a name we'll all recognise – ever wonder how Houdini escaped those handcuffs? Magic! Then, as I'm sure you know, Harry Blackstone, when he first became involved with SHIELD, until surfacing as Harry Potter thirty odd years ago. Of course, with his mobility, it's hard to pin down where and when he first came to the planet, and once you get to the 1800s historical sources become wildly inaccurate." Tony shrugged. "But there you have it."

He'd flicked through the names and dates of each of Harry's aliases on a StarkPad, a photo popping up beside each one. Those same verdant eyes peered out from under a messy black mop of hair in every picture.

"He's immortal," Natasha said, finally realising what that truly meant. His face aged in each life, before returning to perfect youth for each new regeneration.

"Yup," Tony said. "Whatever he's drinking, I want some."

* * *

 _If anybody would like a history of Harry's life, here you go:_

 _1745 – 1790: Henry Hanover Duke of Cumberland - British nobility_  
 _1790 – 1826: Harry Moore - American soldier_  
 _1819 – 1891: Harry Power - Horse thief sentenced to Australia_  
 _1874 – 1926: Harry Houdini - Magician_  
 _1935 – 1997: Harry Blackstone - Magician, actor, author (SHIELD Agent)_

 _There's overlap in the dates because Harry doesn't want to subject himself to being a child, and merely makes up his year of birth. These are all real people._


	4. Chapter 4

"Hungry?" Harry asked. Loki flinched, his eyes snapping open. Harry pushed a plate of food toward him; bangers and mash, stolen from the helicarrier mess.

"You," Loki said, his voice flat. Harry smirked and bit into his own sandwich, leaning back against the warded glass.

"Me."

Loki eyed the food warily, but seemed to deem it safe enough to eat.

"They haven't fed you at all, have they? That definitely violates a few of their laws."

Loki ate the food with grace. He didn't take his gaze off Harry. "They have not," he said. "I don't require as much sustenance as a human nor as frequently, but I do require some."

Harry hummed in agreeance. He snapped his fingers and a pitcher of water appeared, with one glass.

"Thank you." Loki poured himself a drink. "I take it that the surveillance in here is no longer working?"

Harry laughed. "Actually, it is. I've just fiddled with a few minds so that they won't notice anything's wrong until I've gone."

Loki narrowed his eyes, then looked up toward the camera. "Next time, I'd like some mead to go with my meal," he said, obviously addressing his captors.

"If you want proper beer, you're better off going back to Germany." Harry extended a hand, which Loki stared at.

"The stench of death is heavy on you," Loki said, and sniffed, looking away. His shoulders were tense, however, belaying his nonchalance.

"Rude." Harry got to his feet. "See if I feed you again."

"Hopefully," Loki drawled. "You won't have to."

Harry snorted a laugh. "I like you. More so now you're not entirely mad." He captured Loki's jaw between thumb and forefinger, his skin cold to touch, and Loki froze. "Tell me, did Thanos have you for long?"

Loki closed his eyes. "It felt like years," he whispered. "But also, I tumbled through abyss of space for what I thought was an age. I'll never know."

Harry release him and stood back, running a hand through his hair, wondering if the fall from the Bifrost had allowed Loki to get tangled within the fabric of spacetime. Perhaps he really had spent an age plummeting through the cosmos, only to be rescued by one who would become his tormentor. It was certainly a possibility.

Perhaps the Ancient One's advice was to be taken and caution exercised.

* * *

For a woman not even thirty, Hermione Granger was incredibly accomplished, with a doctorate in Mechanical Engineering, another in International Relations and a degree in Law in the works. Natasha knocked on the door of her townhouse, not one Granger would have been able to afford on a student salary, yet somehow, she had. Wealthy parents, Natasha suspected.

Granger opened the door with a bemused smiled upon her lips. She was wearing jeans, with a university hoodie thrown over the top, declaring that she'd attended Oxford. Her feet were bare, her toes painted red.

"Hello? Can I help you?"

Natasha held up her CIA identification badge. "Doctor Hermione Granger? My name is Agent Romanov and I was wondering if I could ask you a few questions about a person of interest that I'm investigating."

To Natasha's intrigue, Granger narrowed her eyes and took the offered badge, inspecting it thoroughly. Only once she was satisfied did she move from the door and return the ID.

"Certainly. Please, come in."

Natasha followed her into the house. It was pleasantly decorated in neutral tones, with a distinctly utilitarian feel to it. Granger showed her to the lounge, shutting the door to a study just off the side of the main room. From what Natasha had glimpsed, the walls of the study had been covered in bookshelves and the desk cluttered with paperwork, a far sight from the rest of Granger's clean and tidy home.

"Can I get you a drink? Tea, coffee?"

"No, thank you," Natasha replied. She opened the folder she'd brought with her and withdrew a picture of Harry from within. Granger frowned, her brows drawing together. She obviously recognised him.

"I was wondering if you could tell me anything about this gentleman?"

Granger took the photo. "I've seen him around the area a few times, most frequently in a café about ten minutes' walk down the road. He watches me, occasionally. I figured he was working himself up to asking me out on a date."

Natasha said nothing. Granger seemed to be telling the truth, but Natasha felt certain that she was missing something.

"What's he done to warrant this level of attention?" Granger asked, tucking an errant lock of curly hair behind her ear as she looked up.

Natasha retrieved the photograph, tucking it away. "I'm afraid that's classified. Is there nothing else you can tell me about him?"

A peculiar smile played across Granger's lips. "He always orders a black coffee and a slice of chocolate cake."

"It seems like you've been watching him too."

Granger shrugged. "I have an excellent memory and an eye for detail."

"I see," Natasha said. "Well, if you think of anything else, please don't be afraid to get in contact." She handed over a business card.

"And if I don't think of anything else?" Granger asked. Her gaze was heated, but not unwelcome. "May I get in contact regardless?"

Natasha blinked in surprise, at both herself and Granger. Granger was shamelessly appraising her and Natasha realised she'd done the same the moment Granger opened the door.

"I can't say I'd object," she said cautiously.

Granger's brown eyes gleamed with delight. "Excellent. I suspect you'll be hearing from me, then." She walked Natasha to the door.

"It was a pleasure to meet you, Agent Romanov."

"And you, Dr Granger," Natasha replied and left in a state of mild shock, wondering what the hell she'd just committed to.

* * *

Harry returned to Loki's cell a few days later. It had been transformed in the time he'd been gone. Loki had a cot and a waste bucket and there was a tray with leftovers from a meal upon it. He was sitting on his bed, reading one of the two books it seemed he'd been supplied with; War and Peace.

Loki didn't flinch upon Harry's arrival, but his muscles tensed. He didn't look up. "You're back."

"Evidently." Harry conjured himself a squashy armchair and settled into it with a sigh.

Loki huffed and snapped his book shut. "Can I help you?" he asked imperiously.

"Oh, certainly," Harry said. He smiled to himself, faintly amused.

They sat in silence, and first seconds, then minutes passed. Harry was perfectly happy to sit there for hours, the serenity of one who knew he had all the time in the world, but he suspected Loki was far too impatient for that.

"Fine," Loki snapped eventually. "What can I help you with?"

"Many things," Harry said airily. "Had second thoughts on that trip to Germany?"

"No," Loki said and that was that.

Harry summoned himself a book and began to read; Agatha Christie's And Then There Were None. It was one he'd read many times before and was relaxing in its familiarity. After a while, Loki took up War and Peace and joined him. He occasionally glanced at Harry, but was beginning to relax in his presence. Harry was absently keeping track of time and eventually someone entered the cell to clear away Loki's tray and replace it with another. They didn't so much as glance at Harry, which was exactly how he intended it.

"Your powers are impressive," Loki said, sometime later. Harry placed a bookmark between the pages of his book and shut it.

"Of course," Harry said with a grin. "I was once a wizard, and used magic long before any of this happened." Harry gestured vaguely at himself, but he could tell Loki understood.

"A human wizard?" Loki said sceptically.

"Yes," Harry said. "But not of this universe." He thought he sounded faintly wistful, and he was. "The Infinity Stones are just the cherry on the top."

Loki stood and began to pace. Harry watched him with his fingers steepled, radiating a faint aura of amusement.

"What do you want of me?" Loki sounded weary, but his gaze was fierce.

"Your company, of course, and I suppose eventually, your trust." Harry smiled, even as Loki shifted uncomfortably.

"The former is yours to take." Loki gestured at his cell. "But the latter… you may never earn."

Harry got to his feet, armchair vanishing as he stood. He winked at Loki, who pursed his lips in disapproval. "I'll be the judge of that. Farewell."

"Until the next time," Loki muttered.

Harry grinned. "Indeed."


	5. Chapter 5

Stark's tech was good, but not good enough to find a rogue immortal when he didn't want to be found. They'd searched for three weeks and not heard a single trace of the whereabouts of either Harry or the Tesseract.

When Thor announced that he intended to return to Asgard, Natasha was not surprised.

"There is trouble brewing," Thor informed them. "My mother has sent me a message asking for my return. I must make haste."

"Need any help?" Stark offered, not looking up from the screen he was tapping away at. Natasha exchanged a look with Clint when Steve frowned at him.

"I'd be happy to help too," Steve added. Natasha hoped that they soon tire of their rivalry.

"You're not going to Asgard, Stark. None of you are," Coulson said with a sigh. After they'd made little progress those first few days, Fury had delegated their weekly meetings to him. They took place in the same meeting room in which she'd first been briefed on Phoenix. Coulson did not seem to be glad of his new job role.

Thor shook his head. "Thank you for your offer, my good friend. But no, 'tis not the place for mortals. My father would not allow it."

Stark seemed to have anticipated this answer, as he merely nodded.

"What exactly defines a 'mortal'?" Natasha wondered, leaning back in her chair. Thor and Harry often used the word, but she knew that the Allspeak did not translate exactly.

"All earth dwellers are mortal," Thor said, then frowned. "Well, bar the Master of Death, of course."

"If he's still on Earth," Stark grumbled.

"No, no, this is a valid question," Bruce said. Natasha turned her full attention to him, although she was always aware of his presence. Bruce rarely spoke, but when he did his input was valuable. "Is the definition 'someone that cannot be killed'? Does it just mean that you have longevity, or that you are harder to kill than the average person?"

"I am of the Aesir," Thor answered. "You are of Midgard. Therefore, you are mortal." He looked dissatisfied with his answer, as though he knew that it was not a sufficient explanation. "My apologies. My brother wields the Seidr. Perhaps he would know."

Natasha had very little inclination to take up the discussion with Loki and knew that Bruce would have even less. Stark, however, had been following the conversation, even if he was pretending not to, and she thought he might eventually become intrigued enough to ask.

"Truly, I must go." Thor stood, hammer jumping into his hand from the floor. "Son of Coul, I require your assistance to free my brother so that I may return to Asgard with him."

Clint, who'd been silent the entirety of the meeting, snorted. Natasha quirked a brow at him but he shook his head in answer.

The group of them proceeded to Loki's cell, drawing attention from all they passed in the corridors. It seemed that not even three weeks could get SHIELD staff used to the sight of Thor in his cloak or Captain America in his stars and stripes.

Loki was reclining on his bed, staring sightlessly at the ceiling. "All of you? What a treat," he drawled. "I do hope you're here to entertain me."

"Loki, danger approaches Asgard," Thor said, striding up to the cell they'd used to contain Loki. "Cease your quarrelsome ways and assist me in helping mother and father."

"He's your father," Loki said with a snarl, before schooling himself calm."No."

Bewilderment crossed Thor's face. "But we are still brothers, are we not? Enough of this nonsense. Son of Coul?"

"Allow me," Clint said. He hit a few buttons on the control panel and the door slid open. Natasha shot him a look. "What? I've been bored. I spent the last few weeks watching his cell from the rafters."

Thor strode into the cell and grabbed Loki's arm, pulling him to his feet. He tried to drag Loki out the door, only to run into some kind of translucent barrier the moment Loki's body exited the door.

Clint snorted. "Loki tried escaping two and a half weeks ago. He didn't get any further than Thor did just now."

"And you didn't say anything?" Steve said. Natasha turned to arch a brow at Clint. Stark was chortling in the corner, still tapping away at his device. Clint shrugged at them in return.

"What is this sorcery?" Thor muttered. He tried to yank Loki through the door, but only managed to send himself tumbling to the floor, Loki still stuck on the other side, looking like an angry, irritated cat.

"The Master of Death has seen fit to contain me," Loki said. He spread his hands, gesturing to his cell, expression impassive. "I will go nowhere he does not wish for me to go."

* * *

Harry hovered on the doorstep to Clint's bedsit, debating whether to knock. The other man had only ever been friendly to him, but SHIELD were undoubtedly unhappy with Harry at the moment. He'd be putting the other man in a difficult situation.

The problem was solved for him when a dog began barking from the other side, having sensed Harry's presence.

"Alright, alright, I'm coming," Clint hollered, before yanking open the door.

They both stared at each other for a long moment before Clint shrugged, pulling the door open wider and catching his dog by the collar before it could bound out.

"I suppose this is the infamous Lucky?" Harry asked, regarding the mongrel. "If it touches me, I will not be held responsible for my actions."

"More of a cat person, are you?" Clint said, then shook his head. "Of course you are. Come on, Lucky, come on now. She's harmless, I promise." He jerked his head and Harry followed him in. Lucky was led to a dog bed and she curled up there, watching the two of them with bright eyes.

"Welcome to my humble abode," Clint said. It was a studio flat, a bed in one corner, a TV and sofa at the centre of the room, and gully kitchen with a sink piled high with plates against one wall.

"Cosy," Harry said.

Clint glanced around and snorted. "Sure. Take a seat, if you want."

The sofa looked safe, so Harry threw himself into one corner of it. Judging by the masses of cushions and a blanket over one arm, he'd bet that Clint occasionally slept on it, or had someone over that slept there. It was comfortable enough.

"Fury is not best pleased with you," Clint said, shoving his hands into his jeans pockets.

Harry smirked. "Is that so? Can't imagine why," he said.

After a beat of silence, Clint snickered. "You jackass. I thought Fury was going to have an aneurysm when he realised that you'd trapped Loki in his cell."

"Perhaps he should have done a better job at containing him, then, if he didn't want my assistance." Harry shrugged. "Loki would have escaped weeks ago if all that had been in his way was glass."

"For some reason, me saying that didn't make Fury any happier," Clint said. He ambled over to one of the kitchen counters and poked at several takeaway menus that were piled up there. "Want some food?"

Harry tilted his head but decided against accepting. Sure, Clint was being friendly, but he wasn't about to push his luck. Instead, he withdrew a mobile phone from his pocket. He chucked it at Clint, who caught it without looking.

"What's this?"

"A cell phone," Harry deadpanned. Clint looked at it and frowned.

"You know, I really should be reporting this in."

"I'll be out of your hair in a heartbeat," Harry said. He wondered if Clint would report to SHIELD, or if he'd withhold in an attempt to gain Harry's trust instead. "Don't make me have to lose that number, whatever you decide."

Lucky barked, before getting up to nose at the menu in Clint's hand. He snorted, ruffling a hand through her fur. Harry was just glad she was well behaved. He wasn't a fan of dogs; Sirius had been the exception that proved the rule. Still, he could appreciate the charms of a faithful pet and Clint had told many stories about her when they'd been assigned to missions together, before Harry had left SHIELD.

Clint looked up at him and nodded. "Alright. I'm going to send you endless cat photos," he said, gaze daring Harry to argue. "So, so many cute pictures of cats."

"I look forward to them," Harry said. He turned to Lucky, fixing her with a stern gaze. "Don't let this one get into too much trouble."

The dog panted. Harry took it as agreement. "Nice seeing you, Clint," he said. "Call me if you need me."

"You too, jackass. Try not to upset any other multinational intelligence agencies."

Harry winked. "No promises."

* * *

When Natasha's phone beeped, she'd expected a message from Clint or Coulson.

Instead, an unknown number popped up on her screen.

 _Agent Romanov, I require your urgent assistance. A beautiful woman gave me her number, but I'm not certain as to whether she'd welcome the idea of a date. —HG_

To Natasha's horror and surprise, she found herself blushing. She tucked the phone into her pocket and continued onto her morning meeting. It was a dull discussion upon what clearance level the information regarding Harry should be given; not something that she had much of a say on, even if she'd been asked to attend. Her phone burned a hole in her pocket the entire morning and her fingers itched to reply, even if she wasn't certain what to say.

"Romanov?"

Natasha snapped to attention and nodded at Sitwell.

"Would you like a coffee?" he said, obviously repeating himself. He was eying her curiously. She supposed she rarely let down her guard enough to ignore someone speaking to her.

"No, thank you," she said. With a subtle glance around the room, she could tell they'd come to a decision and would only spend the next hour confirming it with various departments. "I'm needed in the gym," she said. "If you'll excuse me."

Natasha exited the room before anyone could answer and strode to her quarters. Allowing herself a moment of weakness, she collapsed onto her bed and drew out her phone. The text still sat in her inbox, teasing her.

Eventually, she decided to reply. After all, what harm could it do?

 _I imagine she'd be delighted. And please, call me Natasha. I'll be in London in three days time if you'd like to meet._

Natasha sent the text before she could second guess herself and grinned at the metal ceiling of the room. She thought about the curve of Granger's lips and snorted at her whimsy. Instead, she rolled onto her stomach and added the woman's number to her phone.

It was nice to have a piece of normality to look forward to.

* * *

 _I received a bewildering amount of abuse when last chapter I implied that this story was likely going to become slash. Fuck you those of you that hated and your closed-minded attitudes. I didn't touch this story for over a year because of the response I got to me simply asking if I should ship Harry with Loki or Clint._

 _I can confirm this will be both Harry/Loki and Natasha/Hermione. There will also be straight pairings and I'm considering a triad._

 _Those of you that have stuck with me, thank you. I hope you enjoy this chapter and any more to come that I may post._


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